Sizing fabric



Patented Feb. 8, 1938 PATENT OFFICE SIZING FAB-IO EhnerILBoltoILW Del, assigns-to ilmington, E. I. du Pont de Nemoura & Company, Wilming ton, Del., a corporation of Delaware No Drawing.

i s on...

This invention relates to the sizing of fabrics and more particularly to the sizing of fabrics with low-substituted cellulose ethers.

The sizing of textiles is a process which is old 5 and well-known, and one which is extensively degree of degradation of the cellulose and they extent of alkyiation. Thus, there are the following types of alkyl celluloses:

1. Alkyl celluloses soluble only in organic solvents.

2. Alkyl celluloses soluble in water or organic solvents.

soluble in organic solvents.

4. Alkyl celluloses soluble in aqueous alkali at ordinary temperature but insoluble in water. 5. Alkyl celluloses soluble in water at low temperatures but insoluble in 'water at ordinary temperatures.

6. 'Alkyl celluloses soluble in aqueous alkali at low temperatures, for example, near the freezing point of the solutions, but insoluble in aqueous alkali at ordinary temperatures, for example, 20

C. or higher and insoluble in. water at any temperature.

This invention has as an object the provision of a method of treating fabrics to give them a greatly improved finish as and feel.

A further object is the provision of a textile whose finish is substantially fast to laundering.

A still further object of the invention is a fabric thus treated. Other objects will appear hereinafter.

These objects are accomplished by the following invention wherein a fabric, thread, or yarn is impregnated with an aqueous caustic alkali solution of an alkyl cellulose insoluble inaqueous caustic alkali at ordinary temperature but soluble therein at low temperatures, and the impregnated fabric, thread, or yarn thereafter treated with an acid to insolubilize the alkyl cellulose.

In carrying out the process of the present invention textile fabrics, threads, or yarns are treated with a solution of a low-substituted alkyl cellulose which is soluble in aqueous caustic alkali '5'only on cooling. This particular type of alkyl 3. Alkyl celluloses soluble in water in-' revealed by the appearance Application August 17. 1034. Serial No. 740,288

cellulose, which after once being put into solution at low temperature, may be warmed to room tem- Derature withom: precipitation, is described in copending application of Deane C. Ellsworth and Frederick C. Hahn, Serial No. 681,760, filed July 5 22, 1934. The preparation of these alkyl celluloses is briefly described below in order to define the material to be used in accordance with the teachings of the present invention.

Cellulose is steeped in caustic alkali solution, 10 the excess solution pressed out to leave a moist alkali cellulose which is then shredded. The alkali-cellulose is then aged for longer or shorter time, for example, 7 to 48 hours at 25 C., but preferably not beyond 24 hours at 28 C. or 48 15 hours at 30 C. The aged alkali cellulose is then etherified at temperatures'not above 50 C. andpreferably apm'oximately 40-42 C. with an alkylating agent in amount generally about mole to 1 mole per Cs unit of the cellulose. The 20 etheriflcation reaction is promptly terminated when the desired degree of substitution has been effected. The proper stage of etherification at which to terminate the reaction is readily determined by removing samples of the reaction mix- 26 tum from time to time, placing them in dilute caustic, and cooling to freezing. If a few drops of the solution, warmed again to room tempera,- ture, are then placed between glass plates and the plates pressed'or rubbed against each other, a 30 good product will remain clear, while insoluble iibers will readily be noted'in an incompletely reacted product. In generaL'the products contain from 0.25 to 0.60 alkyl groups per Cs unit of the cellulose. Further details may be found ferring' to the above described application.

The reaction products, upon the attainment of the degree of etherincation desired, may be washed and dried, or may be washed only and pressed out or. may even be used without any 40 purification. In any case, the material is then mixed with sumcient water and caustic to make "a solution of desirable concentration, preferably around'0% of the derivative in aqueous caustic alkali. preferablytit to 8%. This mixture is 45 cooled to a suitable temperature from -5 to -15 C., the mixture being stirred, or the mixture may be frosen. The solution so obtained may be brought back to room temperature, filtered if desired, and used according to the process'of the present invention.

For the purpose of treating textiles, a solution containing from 0.25to 15% of the alkyl cellulose, and from 4% to.9% alkali may be used. Very treatment with less than 0.25% solution of the alkyl cellulose. Solutions containing more than about 15% of alkyl cellulose are difficult to make without too much degradation of the cellulose, and, furthermore, such solutions in general render the fabric too stifl for most purposes, altho for some speciahpurposes such stiffness is of advantage, e. g., in making stiff collars for -shirts. For most purposes, a solution containing from 1% to 10% alkyl cellulose is satisfactory. In general, it is impossible to dissolve this'particular type of alkyl cellulose-in less than 4% alkali, and a solution of caustic more concentrated than about 10% maycause gelation of the-solution. The optimum concentration of alkali is between approximately 5% and approximately 9%.

The process is generallyapplicable to alkyl celluloses soluble in dilute aqueous caustic alkali at low temperatures approximating the freezing point, but insoluble therein at higher temperatures approximating room temperature, e. g., 20 to 25 C. Because of the ready preparation of lower alkyl celluloses such as methyl and ethyl cellulose, these lower alkyl celluloses of the above indicated alkali solubility characteristics, are preferred.

Fabrics, threads, and yarns of all kinds may be treated according to the process of the present invention. Thus, cotton, linen, rayon, wool, and silk yarns, threads, or fabrics, or fabrics such as wool and fur felts may be treated with the particular alkyl celluloses above indicated. Cotton fabrics best lend themselves tothe processes of the present'invention and all types of cotton fabrics ranging from the light voiles and organdies, sheeting material and dress goods, to the heavier Indian Head fabrics and men's suiting materials may be satisfactorily treated with the sizing agents of the present invention.

The textile to be treated is passed thru a solution of the alkyl cellulose, then thru squeeze rolls to remove excess solution. The pressure on the rolls may be varied and likewise the concentration of the solution may be varied in order to regulate the amount of alkyl cellulose sized 0n the fabric. After passing thru the squeeze rolls, the

, fabric is passed into a bath of dilute acid to coagulate the alkyl cellulose on the fabric. Various acids may be used, acetic, sulfuric, and hydrochloric being satisfactory. .The acid bath may be used at elevated or ordinary temperatures, but to avoid tendering the fabric the temperature of the coagulating bath should not be much above F., and the acid concentration should be so chosen as not to exceed thatnecessary to secure complete and rapid coagulation of the alkyl cellulose. A 5% solution of sulfuric acid, or a 75-10% solution of acetic acid has been found to be quite satisfactory, but the concentrations are not to be limited to these values. More or less concentrated acid than above indicated may be used in certain cases. If acetic acid is used to coagulate the alkyl cellulose, the fabric need merely be rinsed after passing thru the acid bath and thru squeeze rolls, and may then be dried or calendered or given any other desired treatment. Because of the strength of the mineral acids, it is desirable to follow a coagulation thereby with a soap scour of about 20 minutes at 120 F. to remove the last traces of the acid from the cloth before drying lest it be tendered by the remaining traces of the mineral acid on drying.

The scope of the process of the present invention is not necessarily limited to an actual liquid coagulating bath. The fabric impregnated with the aqueous caustic alkali solution may be passed thru coagulating chambers containing the vapors of weak organic acids, such as formic or acetic.

These processes are, however, less convenient than the liquid coagulating bath. I

An improved luster may beobtained on textiles, 1

nated under tension or stretched after impregnation or during the coagulation of the alkali cellulose on the fabric.

From the above description of the process it is v evident that a great many factors may be varied.

The exact conditions to be. used in a particular case will depend upon the fabric to be treated and the effect which it is desired to produce.

The following examples illustrate some of the possibilities of the process of the present inven-- tion. These are included for purposes of illustration and not in limitation.

Example 1 Twenty g. of methyl cellulose containing an average of one methyl group for every two glucose units of the cellulose molecule (or, in other words, methyl group per glucose unit) prepared according to the above described process, which is more fully described in U. S. patent application 681,760, waswell mixed with 180 g. of water and allowed to stand one hour to insure complete wetting. To the slurry thus obtained was added 200 g. of a 10% solution of sodium hydroxide cooled to room temperature. The slurry was thoroughly mixed and then cooled over night to -'-20 C. The material froze solid and the fibers of methyl cellulose disappeared. It was allowed to warm up to room temperature whereupon a viscous light-colored solution was obtained.

Example 2 A portion of the solution obtained as in Example 1 above was diluted with an equal weight of 5% solution of sodium hydroxide. A handkerchief lawn was treated with this solution, run thru squeeze rolls to remove excess solution, and immersedfor 2.5 seconds in a bath of 10% acetic acid solution heated to 120 F., rinsed in water and dried by ironing. By this treatment the handkerchief lawn had imparted to it a pleasant and fuller feel and appearance, and a greater degree of stiffness. istics of the fabric were not appreciably affected by laundering for one hour at to F. in

a solution containing 0.25% neutral, soap and V 0.1%

soda ash in a standard launderometer. Ordinary sizes such as starch are practically completely removed by this launderometer test.

Example 3 Example 4 These desirable character A portion of the solution described in Example 1 was diluted to a 3.5% solution of methyl cellulose with 5% caustic solution, and the resulting solution used for treating a piece of hankerchief lawn according to the procedure in Exampl 7 Obtained.

am, it...

' net-tamer nd one than osfabrics prewas AY emP eS-Z M 3- Th f flafi e l relatively laundryi-fast, in comparisonwith iemw iF A ample-or nee-sf .ootton suiting m t ria I ;.L(woven tofllo'ok,like'linen),"was treated'with a;

a 2.5% 1's'o1ut1on J of the-met l cellulose described above, aocordingto the procedure in Example 3. Cf s substantially permanent fl'nlsh stiff and sorne- 'ywhatxlinen-like', was obtained. Ix

Estimat s f Example' d. The treated fabric lwas stlife r and fuller than the treatedfabric' described in Exsizing elect was resistant to -ample' ,5. The

laundering.

mate 1" tion Serial No. 681,760 and obtaining V of a -methyl, group per glucose unit. was thoroughly mixed with 180 g. ofowaterand allowed'to stand 7 one'hour. To the slurry thus obtained was, added 200g. of a 10% solution of hydroxide";

umhydroxide. The resulting solution was used for treating 1 sample of handkerchief lawn accooled to room temperature-. {After thorough mixing theslurry was frozen coolingover night at 20 C. On warminghp toroomtem perature, a .viscous, light-colored solution ,was

Example 8 A portion or the solution'of Example 7 diluted with an equal weight of hydroxide solution to give a solution containing 2.5% methyl cellulose and 5% A sample of handkerchief lawnwas treated with this solu-x tionby the same procedure as described under ,A handkerchief Example 2. The treated fabric'was fuller and stiffer than the untreated fabric and had a more pleasant feel and better appearance. The finish was notremoved by several repeated launderings.

Emmplef' a w lawn was treated according to Example 3 with the solution described in Exampie 8. The results were similar to the results obtained n Example 3.

. a A' portion of the'solutiori described in Example 'l was diluted to 3.5% methyl cellulosewith 5% sodium hydroxide. v This solution was used to treat, a sample ofhandkerchief lawn according to'theprocedure of Example 3. The effects were similar to the effects obtained in Example 3.

Example 11 :A sample of Indlanhead-type fabric was treatedaccording to Example 9. The effects were similar to the efl'ects obtained in Example 5.

. 1 Example 12' An unsized sample of Indianhead-type fabric was treated according to Example 10. The effects were similar to the effects obtained in Exa le Example 13 Twenty so. of'methyl cellulose prepared according to the process disclosed in application Serial Na fper glucose unit .werethoroughly mixed with 180 7 p c ".g. of water and allowedto' standone hour to inth effect produced by ordlnary starch sizes.

sample of 'an- Indianhead--type fabric '(a' coarse harsh cotton fabric), was treated with a r 3 .5% solution of methyl cellulose accordingto;

and Example 9.

6,81,760 and containing ,6 of a methyl group sure complete wetting. To the slurry thus obtained was added 200 g. of a 10% solution of sodium hydroxide cooled to room temperature.

Example 14 Aportion of the solution prepared in Example a 13 was diluted with an equal weightof 5% sodihydroxide to give a solution containing 2.5% methyl cellulose and 5% alkali. This solution was used for treating a piece .of handkerchief lawnaccording. to Example'2. The effect was --'similar to: the

I v effect obtained ln-Example 2 and Example?? v I Es:cmple15- procedure inExample 3. The effects obtained were similar to the eifectsobtained in Example 3 l ratanmze 16 I I i'mosolntion'usod in Example 13 wasdiluted to 3.5% methyl cellulose with a 5% solution of sodi- A sampleofhandkerchief lawn was treated with thesolution' of Example 14 according to the cording to the procedure of Example 6. The

f treated fabric was similar to the fabrics obtained in Example 4 and Example 10.

Example 17 An Indianhead-type cotton fabric was treated according to Example 16.- A substantially permanent sizing and stiffening'effect was obtained similar to that obtained in Examples 6 and 12.

Example 1:

' i 5%solution was made, by the procedure of Example 1, of a methyl cellulose-prepared according to the process disclosed in application Serial No. 681,760 and containing V methyl group per glucose'unit. A sample of 48/48 cotton fabric was impregnated with this solution, run thru Isumple 1s A portion of the methyl cellulose solution described in Example 10 was diluted to 2.5% methyl cellulose with sodium hydroxide and used to treat a piece of-48/48 cotton fabric according to the procedure of Example 18. A good sizing effect.

was obtained but less pronounced than in the preceding example. The-finish imparted rather linen-like properties to the fabric'and was not removedby laundering one hour at the boil in 0.5% neutral soap solution.

trample 20 A sample of unfinished cotton voile was treated with the methyl cellulose solution described in Example 18, then immersed for 2 minutes in 5% acetic acid to coagulate the methyl cellulose on the fabric. The fabric was then rinsed and dried by ironing. An organdy effect was obtained which was not lost on laundering.

Example 21 The solution described in Example 18 was diluted to 2.5% methyl cellulose with 5% sodium hydroxide and the resulting solution used for treating a 48/48 unfinished cotton fabric. The fabric was then immersed for 3 minutes in sulfuric acid at 120 F. to coagulate the methyl cellulose. rinsed thoroughly, and dried by ironing. A substantially laundry-fast finish was obtained.

Example '22 A 48/48 unfinished cotton fabric was sized as in Example 21 except that 25% acetic acid was used instead of 10% sulfuric acid for coagulation of the methyl cellulose. The results were substantially the same as those obtained in Example 21.

Example 23 A sample of 48/48 fabric was treated as in Example 21 except that 10% acetic :acid was used instead of 10% sulfuric acid to coagulate the methyl cellulose. The results obtained were comparable with those obtained in Example 21.

Example 24 A sample of 80/60 cotton fabric was treated according to the procedure of Example 21 except that 10% acetic acid was used insteadof 10% sulfuric acid to coagulate the methyl cellulose. A substantially permanent, rather linen-like flnish, was obtained.

Example 25 A sample of 80/60 cotton fabric was treated with a 10% solution of methyl cellulose in 6% sodium hydroxide, the methyl cellulose containing approximately one-half methyl group per glucose unit. A substantially permanent finish was obtained.

Example 26 An unfinished cotton fabric was impregnated with a 5% solution of an ethyl cellulose containing of an ethyl group per glucose (Cs) unit. The solution. was prepared by treating the ethyl cellulose with a 7% sodium hydroxide solution A light unfinished cotton fabric suitable for an organdy finish was treated with a solution ofa methyl cellulose in 6% caustic, the methyl cellulose containing one-half methyl group per'glucose'unit. After impregnation, the

. fabric was treated in a bath of 0.5 molar sulfuric acid and 0.5 molar sodium sulfate. A stiff, organdy effect was obtained on the fabric.

Instead of the coagulation bath used :in Example 27, any -of the following baths will give satisfactory results: 1. Acet "acid (2.0

molar, or approximately 12%) 2. Sulfuric acid (0.5 molar) plus sodium chloride (1.0 molar).

3. Sulfuric acid (0.5 molar) plus ammonium sulfate (0.5 molar).

4. Sulfuric acid (0.5 molar) plus magnesium sulfate (0.1 molar).

5. Sulfuric acid (0.5 molar) plus potassium chromium sulfate (0.1 molar).

6. Sulfuric acid (0.5 molar) plus stannic ammonium chloride (0.1 molar).

7. Acetic acid (2.0 molar) plus sodium acetate (0.5 molar).

8. ((1) Sodium sulfate (2.0 molar) followed by (b)' sulfuric acid (0.5 molar).

9. Ammonium sulfate (18%) plus ammonium hydroxide (0.2%) followed by (10) (l1) or (12).

10. Sulfiu'ic acid (11%).

11. Sulfuric acid (8%) plus sodium sulfate (26%), plus dextrose (4%).

Sulfuric acid (13%) plus sodium sulfate o). I

As compared with treatment of fabrics with 'alkyl celluloses from organic solvent solutions,

the process of the present invention has certain "advantages. One class of these advantages deals harsh effect and a more linen-like finish. This is probably connected with the greater penetration of the sizes of the present invention.

The above description and examples are intended to be illustrative only. Any modification of or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims.

I claim:

1. Process of sizing fabrics with water insoluble methyl cellulose which is dissolved by aqueous caustic soda at low temperatures approximating the freezing point but not dissolved by the same at ordinary temperature, which comprises impregnating a cotton fabric with a solution containing approximately 2.5% of said methyl cel-' lulose containing approximately /2 methyl group per glucose unit, said solution also containing approximately 5% caustic soda, removing excess solution from the fabric and coagulating the methyl cellulose on the fabric by treatment with 10% acetic acid, and thereafter drying.

2. The process of producing adherent water insoluble laundry-fast sizing on fabrics with water insoluble methyl cellulose which is dissolved by dilute aqueous caustic soda at low temperatures approximating the freezing point but not by the same at ordinary temperature, which comprises impregnating a cotton fabric with a dilute aqueous caustice alkali solution of said ethyl cellulose, and thereafter coagulating the ethyl cellulose on the fabric by exposure to a weak acid.

v 4. The process of producing adherent water insoluble laundry-fast sizing on fabrics with water insoluble lower alkyl cellulose which is dis- "solved by dilute aqueom caustic soda at low temperatures approximating the freezing point-but not dissolved by the same at ordinary temperature, which comprisa impregnating a cotton fabric with a dilute aqueous caustic soda solution of said lower alkyl cellulose, and thereafter coagulating the lower alhl cellulose on the fabric by exposure to a dilute acid.

is 5. The process of producing adherent water jinsoluble laundry-fast sizing on fibrous insterials with water'insoluble lower alkyl cellulose which is dissolved by dilute aqueous caustic alkali at low temperatures approximating the freeing point but not dissolved by the same'at ordinary temperature. which comprises impregnating a fibrous material with a dilute aqueous caustic soda solution of said lower alkyl celulose, and thereafter coagulating the lower alkyl cellulose onithe fibrous material by exposure to a dilute acid.

3 v insoluble laundry-fast sizing on fibrous material which comprises impregnating a fibrous mate- 6. The process of producing adherent water rial with a low substituted water insoluble lower alkyl cellulose dissolved in aqueous caustic soda of 440% strength, said alkyl cellulose being water insoluble and undissolved by dilute aqueous caustic soda at room temperaturerbut dissolved therein at temperatures approximating the frees- 'ing point and-thereafter coagulating the said alkyl cellulose on theflbrous material by treat-' mentwith an acidic coagulant.

7. A fabric having an adherent water insoluble laundry-fast sizing of a low substituted water insoluble lower alkyl cellulose, said alkyl cellulose being water insoluble and undissolved by.

' dilute aqueous caustic soda at room temperature but dissolved therein at temperatures approximating the frec in Point.

8. A fabric having an adherent water insoluble laundry-fast sizing of a low substituted water insoluble lower alkylcellulose, said lower alkyl cellulose being water insoluble and undissolved by 6% aqueous caustic soda at room temwater insoluble methyl cellulose, said methyl cellulose being water insoluble and undissolved by 4% aqueous caustic soda at room temperature but dissolved therein at temperatures approximating the freezing point.

11. A fibrous material having an adherent coating of a low substituted water insoluble lower alkyl cellulose, said allryl cellulose beim of such degree of substitution and degradation that it is undiaolved by 6% aqueous caustic soda at ordinary room temperatures but is dissolved by 6% aqueous caustic soda at temperatures above and near the freezing point thereof, the said 'coatim constitutingv a laundry-fast water insoluble sizing.

12. The process of producing adherent water insoluble laundry-fast sizing on fibrous materials which comprises impregnating fibrous material with a dilute aqueous caustic alkali solution of a water insoluble lower alkyl cellulose and thereafter coagulating the lower alkyl cellulose on the fibrous material, the said alkyl cellulose being water insoluble and undissolved by dilute aqueous caustic bda at ordinary room temperatures but dissolved by aqueous caustic soda at temperatures above and near the freezing point thereof.

13. The process of producing adherent laundry-fast sizing on textiles without deieteriously affecting the water absorbtivity oi the textile which comprises impregnating the textile with a dilute aqueous caustic soda solution oi a water insoluble alkyl cellulose whose alkylsubatituents belong to the group consisting of ethyl and methyl, and thereafter coagulating the alkyl cellulose on the textile by treating the impregnated material with a dilute acid, the said alkyl cellulose being or such degree 01 substitution 'and degradation that it is not dissolved by 6% I lneous caustic soda at ordinary room temperatures but is dissolved by 6% aqueous caustic soda at temperatures approximating the freeaing point.

4 g I ELMER K BOLTON. 

